Reforestation projects often involve hand planting of seedlings. At one time, reforestation workers used tools called "mattocks" to plant seedlings. The mattock's blade was driven into the ground and used to pry a "V" shaped hole in the ground. A seedling was dropped into the hole and the mattock's blade then removed, allowing the ground to close around the seedling's roots. Because the mattock merely sliced a narrow hole in the ground, without loosening the surrounding earth, the seedling's roots were often unable to develop. Accordingly, relatively large numbers of seedlings planted with the aid of mattocks failed to mature into trees.
More recently, reforestation workers have used shovels to plant seedlings. The shovel is used to prepare a planting spot of reasonable size by exposing the soil and loosening or breaking it up to a suitable depth. Seedlings planted in such prepared planting spots are more likely to take root and mature into trees. However, preparation of such planting spots requires comparatively expensive, time-consuming manual labour and is accordingly unsuitable for large scale reforestation projects.
The present invention provides a mulching apparatus which may be mounted at the end of the boom of an excavator type vehicle. The machine operator actuates and manoeuvres the vehicle, boom and mulching apparatus to rapidly prepare a large number of planting spots in which seeds or seedlings may be planted. Teeth provided on the mulching apparatus expose and break up the soil, together with any organic material therein such that, when the mulching apparatus is withdrawn from the ground, a mulched residue remains within or adjacent to the periphery of the resultant planting spot. Seeds or seedlings are deposited in the prepared planting spot. The mulched residue can be readily placed over the seeds, or over the seedlings' roots.
The prior art has provided a variety of powered devices for tree planting and the like. For example, U.S. Pat. No. 3,561,540 issued 9 February, 1971 for an invention of Kaszkurewicz discloses a device for planting trees or the like. Unlike the present invention, Kaszkurewicz' device does not prepare a mulch-containing planting spot. By contrast, Kaszkurewicz' device comes into operation only after the tree or other item to be planted has been deposited into a hole dug by other apparatus. Kaszkurewicz' device is lowered over the top of the item and rotated. Blades on the device move soil from the area surrounding the previously dug hole and deflect that soil into the hole atop the item's roots, in such a manner that an annular trench is created in the soil around the periphery of the planted item.
U.S. Pat. No. 4,287,955 issued 8 Sep., 1981 for an invention of Anderson provides a rotary tilling device capable of attachment to a manipulable vehicle boom through which driving power is supplied to the device. A series of downwardly depending teeth are arranged around the periphery of a rotatable drive plate provided at the end of the boom. Anderson's device tills the soil between cultivated plants. The configuration of Anderson's teeth is such that it is unlikely that his device would provide a practical means of preparing a mulch-containing planting spot, as the present invention does.
U.S. Pat. No. 4,332,299 issued 1 Jun., 1982 for an invention of Parks et al. provides another type of cultivator device comparable to that of Anderson. Again, the object appears to be to till the earth between or near cultivated plants; not to facilitate planting or mulching operations. In particular, like Anderson, Parks et al. provide teeth around the periphery of a rotatably driven base plate. However, the teeth do not appear to be configured in such a manner that they would provide a practical means of preparing a mulch-containing planting spot.
U.S. Pat. No. 4,570,721 issued 18 Feb., 1986 for an invention of Mentele provides a device for use in certain weeding operations. A series of downwardly depending teeth are provided around the lower underside of a rotatable drive plate. The ends of the teeth are curved somewhat inwardly. However, the curvature does not appear to be sufficient to ensure that the Mentele device would prepare a mulch-containing planting spot if the rotating teeth were forced vertically downwardly into the earth. It seems that the teeth would merely cut an annular hole into the earth, leaving a solid cylindrical core in the centre of the hole. This is unsuitable for tree planting operations of the sort contemplated by the present inventor.
U.S. Pat. No. 4,854,404 issued 8 Aug., 1989 for an invention of Weber et al. provides a tucket auger for excavating holes for tree transplantation. One embodiment of the Weber et al. device employs spaced arrays of vertically aligned teeth which are arranged at intervals around the outer surface of a rotatable, funnel-shaped member. The rotating device is driven into the ground. The teeth dig a hole in the ground and force the removed dirt through slots into the interior of the funnel. The device, with its contained dirt, is then removed from the ground, leaving a hole to receive a tree. The funnel may then be opened in clam-shell fashion to dump the contained dirt back onto the tree's root ball. The present invention avoids the mechanical complexity of the Weber et al. device by simultaneously preparing a planting spot and leaving mulched residue within or adjacent to the periphery of that spot.
U.S. Pat. No. 4,936,390 issued 26 Jun., 1990 for an invention of Anderson et al. provides another type of device for tilling the soil around cultivated plants. Again, a series of downwardly projecting teeth are provided around the circumference of a rotatable base plate. The configuration of the teeth is such that it is unlikely that this device could constitute a practical mechanism for preparing a mulch-containing planting spot, as is accomplished by the present invention.